Weapon-mounted firearm accessories have become an important tool for military, police, militia, and civilian firearm users. Examples of popular firearm accessories include targeting devices, such as LASER sighting devices, and target illuminators, such as flashlights. Many firearm designs incorporate mounting rails for supporting these accessories. Using an accessory rail interface, a given accessory may be mounted to a variety of firearms or firearms platforms. Likewise, if a particular firearm includes a rail interface, a variety of accessories may be interchangeably mounted to the firearm. The interchangeability of accessories is of particular importance to military and law enforcement personnel attached to special operations units, as this allows a single firearm to be reconfigured to meet certain mission specific needs.
A number of weapon-mounted firearm accessories can be used to facilitate aiming the weapon. Laser sights for weapons permit a user to aim a weapon by projecting a light beam onto a target. Laser sights permit a user to quickly aim a weapon without viewing the target through a scope or other sighting device. This also permits the user to aim and shoot from any number of other firing positions, such as permitting the user to shoot from the hip. If the laser sight is properly sighted for the distance and wind conditions involved, a projectile, such as a bullet, arrow or shot, from a weapon will strike the desired target where the light dot generated by the laser sight shines on the target.
Laser sights are not, however, without problems. For example, although laser sights work well in low light conditions, in bright light conditions laser sights occasionally perform poorly because ambient light can overwhelm the dot generated on the target by the laser light source, making the dot difficult or impossible for the user to see. A laser sight also uses a relatively large amount of power, so the battery life for a laser sight is typically relatively short.
Examples of electronic sights for weapons include reflex sights and holographic sights. Electronic sights use a light source to project a narrow beam of light onto a specially coated lens. The lens reflects the light to the eye of the user, and the user sees the light as a small, colored dot on the lens. The user aims the weapon by viewing the target through the lens and positioning the dot on the target. If the electronic sight is properly zeroed or sighted for the distance and wind conditions involved, a projectile from the weapon will strike the target at the position on the target covered by the dot on the lens. Electronic sights offer many advantages over conventional sights in any number of firing situations. For example, typical telescopic sights require a user's eye to be carefully aligned behind the scope and require a particular eye relief, requiring the user's eye to be a particular distance from the scope lens, typically around three inches. This makes scopes difficult to aim quickly, difficult to use while tracking a moving target and difficult or impossible to use with weapons such as pistols or bows. Electronic sights overcome these problems in that they do not require any particular eye relief and do not require, relatively speaking, the careful alignment of the user's eye relative to the lens. If the user can see the light dot reflected from the lens, the user can aim the weapon, and a projectile fired from a properly sighted weapon will strike the target at the point on the target covered by the light dot on the lens, regardless of the alignment of the user's eye relative to the lens.
Electronic sights are also not without problems. For example, electronic sights still require a user to view a target through a lens and, therefore, do not offer the aiming flexibility discussed above in connection with laser sights. As with a laser and other sights, an electronic sight is zeroed or sighted for a particular distance, and adjustments in the field are also typically inconvenient or impractical. Electronic sights also have the potential to stop functioning in the field. For example, the battery of the electronic sight may become depleted.